libpf: drop Hash64 #1107

Job	Run time
Check licenses of dependencies	51s
Build integration test binaries (amd64)	1m 42s
Check for differences in the eBPF binary blobs	38s
Lint (amd64)	1m 35s
Build integration test binaries (arm64)	1m 27s
Lint (arm64)	2m 48s
Test (amd64)	2m 53s
Test (arm64)	2m 22s
Test rust components	55s
Integration tests (v4.19.314 amd64)	2m 8s
Integration tests (v5.4.276 amd64)	1m 53s
Integration tests (v5.10.217 amd64)	1m 54s
Integration tests (v5.15.159 amd64)	2m 58s
Integration tests (v6.1.91 amd64)	6m 32s
Integration tests (v6.6.31 amd64)	1m 53s
Integration tests (v6.8.10 amd64)	1m 41s
Integration tests (v6.9.1 amd64)	1m 49s
Integration tests (v6.6.31 arm64)	3m 40s
Integration tests (v6.8.4 arm64)	3m 53s
Integration tests (v6.9.1 arm64)	3m 46s
	47m 18s

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